1. Field of the Invention
This invention relates to a new method and apparatus for developing electrostatic latent images and, in particular, to those methods and apparatus using liquid developers.
2. Description of the Prior Art
The conventional electrostatic developing methods have been performed by both dry developing methods and liquid developing methods. Typically, electrostatic latent images are formed on a sensitive plate, which may alternatively take the form of a photoconductive layer of selenium disposed on a conductive substrate; a space charge type of sensitive plate comprised of an insulating film disposed on a surface of a photoconductive layer of cadmium sulfide; or a sensitive plate which is coated with a photoconductive fine powder such as zinc oxide, titanium oxide, etc., mixed with a resin binder and coated on a conductive substrate. The electrostatic latent images are developed by attracting in a dry process charged, fine colored particles to the electrostatic images by electrostatic forces in the case of dry developing, or by electrophoretically attracting to the latent image charge, in a liquid process, fine colored particles suspended in a liquid carrier of high resistance and low dielectric constant.
In these methods, however, there were defects, such as the scattering of the developer powder, the complexity of the developing apparatus, the low resolution of the reproduced images, in the case of the dry method; and defects, such as, the odor, poison, risk of fire due to the discharge breakdown, of the liquid developer in the case of liquid developing.